A47B96/00—Details of cabinets, racks or shelf units not covered by a single one of groups A47B43/00 - A47B95/00; General details of furniture

A47B96/14—Bars, uprights, struts, or like supports, for cabinets, brackets, or the like

A47B96/1408—Bars, uprights, struts, or like supports, for cabinets, brackets, or the like regularly perforated

Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

In the standard practice of forming structures from elements such as plane angle bars the drilling of the holes in the respective elements of the structures to receive bolts, rivets or the like fixing means must be performed in advance according to the appropriate measurements, or must be effected in situ. Either method entails considerable expenditure of time and labour. Consequently attempts have been made to design standardized constructional elements such as angle bars wherein holes or slots for the fixing means are pre-formed in the element itself according to a fixed pattern capable of mass production, the said holes or slots being located in such positions as to afford a number of possible ways of assembling two or more of the elements together. Such elements are usually subject to certain limitations in respect of modes of assembly or adjustability.

An object of this invention is to provide a novel constructional element having pre-formed slots for fixing means, the slots having a shape and formation permitting a high degree of flexibility in respect of the number of possible modes of assembly, and allowing a high degree of adjustability between the elements when securing them together in difierent modes of assembly.

A further object of the invention is to provide a prefabricated constructional element in the form of an angle bar slotted to receive fixing bolts and having universal adjustability for joint making at least in the case of two bars at right angles, whilst also permitting the formation of joints at other angles and of a telescoped joint between two bars.

A further object is to provide a pre-fabricated bar slotted such that square shank fixing bolts may be universally employed for parallel or right angle joints.

A further object is the employment of standardized slotted bars with a special form of square shank bolt allowing the making of joints between two bars at any angle.

A further object is to provide a pre-fabricated angle bar slotted to receive fixing bolts and permitting the making of bolted or the like joints between parallel bars or two bars at right-angles, employing in either case the minimum number of bolts and without trimming off waste sections from either bar.

According to the present invention a constructional element or bar or the like form is provided with a row of uniformly spaced slots inclined to the length of the bar such that when two such elements are superimposed at right-angles the said slots provide an infinite number of adjusted positions of the two elements in the directions of their respective lengths in each of which positions there is partial coincidence of the slots sufficient for at least one fixing bolt of thickness equal to the slot width.

A particularly preferred embodiment of the invention rates I atent ice is that in which the slots are of chevron or like shape, and the most useful form of constructional element for all practical purposes is a bar of right-angle section having one row of equally spaced slots in each limb or flange thereof arranged on a line parallel to the length of the bar. In one case the two flanges of the bar may be identical as regardstheir dimensions and slot formation. In another case the flanges may differ in width and in the slot dimensions; and such a non-symmetrical bar has certain advantages over the symmetrical type. The slots are spaced at constant-pitch on the longitudinal centre line of each limb or on a line parallel thereto. The relation between the pitch and the dimensions of the slots may be various in order to obtain universal adjustability. In the case of symmetrical chevron-shaped slots, it is preferred to make the slot pitch equal to the hypotenuse of each chevron shaped slot measured inside the arms of the slot.

A further preferred embodiment comprises a rightangle section bar as above described in which the limbs are of difierent width, the narrower limb having preferably a single row of equal-armed slots of chevron shape centred thereon, and the wider limb having a single row of L-shaped slots whose shorter arms are equal to the arms of the chevron slots of the first mentioned limb. The merits of such L-shaped slots will be described hereinafter in more detail.

A further feature of the invention is a joint made between two or more of such bars, either of the type having equal flanges, or the type having unequal flanges, with a type of coach bolt whose square shank is not greater than, and preferably equal to, one thickness of the flange of the bar.

In order that the above and other features of the invention may be more readily understood, examples of preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings, in which,

Fig. 1 is a perspective view of a portion of a constructional element according to the invention;

Fig. 2 is a perspective view of one form of inside rightangle joint made between two of the elements shown in Fig. 1;

Fig. 3 is a cross-section of the joint shown in Fig. 2 along the line III-III of Fig. 2 and showing a preferred form of fixing bolt;

Fig. 4 is an elevational view of an outside right-angle joint showing a maximum of coincidence of the fixing slots;

Fig. 5 is an elevation of one form of joint where the elements have their long axes parallel and showing one postion of minimum slot coincidence;

Fig. 6 is a cross-section through the joint of Fig. 5 along the line VI-VI;

Fig. 7 is a view, partially in perspective, of another form of constructional element;

Fig. 8 is an elevation of an outside right-angle joint between two elements showing one position of minimum slot coincidence;

Fig. 9 is an elevation of a lap joint;

Fig. 10 is a perspective view of one form of right-angle joint between three elements;

Fig. 11 is a fragmentary view showing part of a joint between two elements at an oblique angle;

Fig. 12 is a perspective view of another form of fixing bolt.

Referring now to the drawings and in particular to Fig. l, the constructional element comprises an angle bar of right-angle section having in each of its equal limbs or flanges 1 and 2 a row of chevron shaped slots spaced at constant pitch and centred symmetrically on the long axis of each limb.

7 2i} and; the underlying slots 4 and 5 of bar 21.

The relative dimensions and spacing of the slots is shown most clearly in Fig. 3 where the slot width is 7 indicated as c, and the pitch d of the slots, i. e. the distance measured between the apices of successive chevron slots,is equalttothe hypotenuse measured inside the arms of each slot, so that'the inside length of each army With the right-angle chevron slot shown, the condition for universal adiustability of two elements at right-angles, i. e. an overlapping of slots in all positions giving access for at least one bolt of diameter equal to the slot width is that the pitch a 7 d2v2e' The strength of the element will however depend on the amount and situation of the removed metal, and will therefore depend on the dimensions of the width 0 and of the pitch d, and itis therefore preferred to take the limiting case where I V d- /2e Inrespect only of'universal adju stability the width c of the slots is' notcriticalfand may be chosen to suit the climensions'and material of the element having regard to the possible'stresses whichmay be established in use and to theistandard bolt sizes available for fixing. in the construction shown it is preferred to use a metal bar for example of rolled steel or light alloy of standard dimensions; the width a of each limb 'may be 2 inches and the thickness b will vary according to the material of the bar. 7 In a metal bar of the dimensions above described the preferred dimensions of the slots are as follows:

. 1;ii1 n; A inch Where non-metallic materials are used, for example plastic, the thickness may be increased to obtain the desired rigidity of the bar. 7

'With such dimensions, the pitch of the slots may be employed as a measured a bar length and corresponding that shown' in Fig. 2. Between the position of maximum overlap of slots as shown in Fig. '4 and minimum overlap as shown in Fig. 2 an infinite degree of intermediate adjustrnent is possible in either of the two directions at right-angles for either of the joints. In the joint of Fig. 4, as contrasted with that in Fig. 2, the elements are not held at right-angles by the abutting of a square end of one marks may be made on the bar at every 12th slot for example in the position 1. Although any random lengths may be utilized, it is preferred to begin an'uncut bar at an integral number of pitches from'a mark and to mark every twelfth'slot from the bar end;

Referring now to Fig; 2, a joint is shown between random lengt'hs oftwo' similar bars indicated generally byltl and 21 and having their corresponding flanges numbered 1 and 2. The bars. are placed at right angles and one Within the other, the slot coincidence being of the minimum order and allowing the insertion of only'one fixing bolt A at the point of overlap of the slot 3 of bar positions of overlap giving 2, 3 or more bolt positions may be obtained byrelative motion of the bars in the direction of their length or transverse thereto.

Other 7 As shown'in Fig. 3 it is preferred to use a fixing bolt of coach type. wherein the length of the squared shank is equal to the thickness b of the metal, and whose side of the squared shank is equal to the width c of the slot, so that the bolt is automatically locked against turning by its square shank fitting'the walls of the slot in 'one flange oniy. This joint is partly stabilizedby'the squared ends of the inside bar'20 abutting against the flanges of the outside bar 21;

It will be understood that by reversing one or the other of the bars20or'21, an outside joint may be formed; 7

Fig. 4 shows an elevationof such a joint, where the parts are adjusted to give the maximum degree of overlap betweenithe slots, thus providing for three difierent single bolt positions where slots 6 and '7 overlap; slots 8 and 9,

7 and, addition, complete coincidence of one half of slot 7 and one half of: slot 9. In the joint of Fig. 4, a minimum overlap position may be found corresponding to element against the inside flange of the other elementgand in such 'a case it may be convenient to use a type of coach bolt in which the length of the squaredshank is equal to 1 /2 times the thickness b of the metal, so that upon insertion of the bolt the two elements are held at rightshank whilst the nut is' being of overlap for this kind of joint gives three bolt positions 7 7 per slot pair. V l

Fig. 7 is a partial perspective view of another preferred form of constructional element comprising a right-angle L-section bar having one flange 1 identical with the iiangel of the bar shown in Fig. l, and a'second flange 2 of greater width g. In the wider flange 2 the slotsare non-symmetrical, and as shown each L-shaped slot has'ai short arm of inside length e and'a long arm of inside; length 2e. The pitch, and other dimensions of the slots are as in the bar shown in Fig. l. The alignment of the slots in the adjacent-flanges 1 and 2 is shown by the line X'.Y, from which it is .seen that the ends of the longer arms 1d ofthe slots lie intermediately between the pro jections on; to the line of bend of the adjacent'arms 11 of the slots in flange i minimum slot cross-section on a transverse section through the bar andis therefore conducive to resistance to shear and bending stress. For the same reason the spacing h of the slot ends 16 from the angle of the bar is made greater than the spacing m of the slot ends. 11 from the angle of the bar, thus increasing the total cross-section of metal atthe'bend without unduly increasing the total weight per unit length,

'8 is an elevation of'a; right-angled joint between two identical bars of the kind illustrated in Fig. 7. This joint is of the general type illustrated inFi gt; 4, but in the ssen e! being describ d the is ho n n f h p itions of minimum coincidence between the slots in a wide flange ,3? of one bar and a similar wide flange 2 o f a "second bar. The positions of. overlap of slots where connecting bolts may be inserted are indicated at 12 and 13, and these bolts maybe either of the kind; shown in Fig. 3 or of the kind having a square shank'of length greater .than themetal thickness, for example l /z timesthethickness, as already describedabove. A position of partial v I coincidence between the slots may be obtained with any random length of flange 2?, but in the present casethe .degree of minimum coincidence allows for two fixing bolts. It will be'understood by comparison of 'thejoint of Fig. 8 with the joint of Fig. 4 that other, positionsof partial coincidence of the slots may be found for the joint shown in fig. 8, which will give more than two positions for fixing bolts up to a maximum which will be obtained when the bars are in relative positions equivalent to that shown in Fig. 4. a r V Fig. 9, is. an elevationof a telescoped lap joint made the bars may be longitudinally adjusted to'give partial Such an arrangement gives a overlap for the insertion of two or more bolts in a number of difierent positions. This is true also for a telescoped lap joint of two bars of the type shown in Fig. 1.

As an example of the adaptability of the constructional element in joint making, one form of right-angle joint between three random lengths of bar is shown in Fig. 10, where the narrow and wide flanges of the respective bars are indicated by 1 2 1 2 and 1, 2. The coincidence of slots gives a choice of bolt fixing positions for the bar flanges in three planes at right-angles. Three bolts, one in each plane, for example at positions C, D, and E, are sufiicient for locking the three lengths of bar together in the position shown, but further bolt positions are available if required.

Fig. 11 illustrates how the bolt of the kind shown at A in Fig. 3 may be used also for oblique joints. The flanges of the two bars are indicated respectively by 1*, 2 and 1 2 In the bolt position shown at F, the parallel sides of slot 17 of flange 2 retain the squared shank of the bolt whilst the threaded shank projects through slot 19 of flange 2 The conditions are similar but reversed if the bolt is placed first through flange 2 Fig. 12 shows an alternative form of bolt, which may be used in joints which are only accessible from one side of the structure. The bolt head is cast or ground to a thickness 0 equal to that of the squared shank, which is itself equal to the width of slot, so that the bolt may be passed head-first through one of the slots, and thereafter turned at right-angles to bring it into the fixing position. In this case also the length of the squared section of the shank is equal to the thickness b of the metal, but it may be made greater than one thickness and less than two thicknesses as already described above.

Although all the possibilities of joints and composite beams have not been illustrated, it will be evident to those skilled in the art of constructional elements, that many other modes of assembly and constructional forms made up of the elements herein described and shown in the drawings are possible and that in every case where two bars of the type shown in Fig. 1 are at right-angles, at east one fixing bolt position is oflered between the two bars thus giving an infinite number of adjusted positions in the directions of the lengths of the respective bars.

In the case of a bar of the type shown in Fig. 7 at least two fixing bolt positions are offered in every position of two bars at right-angles.

Where the bars are arranged with their long axes parallel and the slots pointing in opposite directions, partial coincidence of the slots can always be obtained suflicient for the insertion of at least one bolt in the case of the bars shown in Fig. 1, and two bolts in the case of the bars shown in Fig. 7.

Where the bars are arranged with their long axes parallel and the slots pointing in the same direction, bolt fixing positions are found at intervals depending on the pitch of the slots, and hence at least one bolt position can be found over an adjustment range not greater than the slot pitch.

Modifications may be made in the relative dimensions and formation of the slots whilst retaining the benefits of the invention. For example a slot may be used having each arm of inside length 2e, which, in the case of a bar of the kind shown in Fig. 7, would necessitate a flange width greater than g, but would result in a greater possible number of bolt fixing holes for each adjusted position of the bars. Furthermore, the slots need not be of continuous chevron shape but may be interrupted, for example at the apex by a web or webs of metal resulting in a corresponding increase in strength, but a decrease in the adjustability for fixing purposes, since such connecting webs will not be available as bolt apertures.

I claim:

1. A prefabricated constructional element comprising an L section angle bar having flanges of difierent width and slotted in each flange at equal intervals to provide fixing holes for bolts of diameter equal to the width of such slots to secure two of such elements together, the said slots being of right-angle chevron shape similarly directed and with the arms directed substantially at 45 to the long axis of the bar and the pitch measured between the apices of adjacent slots being not greater than the hypotenuse measured across the arms of the slots; the apices of the slots all lying on a line parallel to the long axis of the bar.

2. The prefabricated constructional element as claimed in claim 1 wherein a series of slots in the one flange are similarly oriented to a similar series of slots in the other flange of the bar and the slots in the respective flanges are identically placed with respect to a plane at right-angles to the long axis of the bar.

3. A lap joint comprising two similar L-s'ection angle bars placed with their long axes at right-angles, each of said bars having its flanges of diflerent width, a series of slots equally spaced along the length of the flanges of each bar, said slots being of right-angle chevron form similarly directed and with the arms directed at 45 to the length of the bar, the pitch measured between apices of successive slots being not greater than the hypotenuse measured across the arms of each slot, the apices of the slots of each bar lying on a line parallel to the long axis of the bar, and bolts passing through the intersection of two slot arms at right-angles in overlapping flanges of the respective bars, said bolts having shank portions of length not greater than one thickness of a flange shaped to lock in one of said intersecting slots of the two overlapping flanges.

4. A box joint comprising three similar L-section angle bars placed with their ends abutting and their respective long axes mutually at right-angles, each of said bars having its flanges of diflerent width, a series of slots equally spaced along the length of the flanges of each bar, said slots being of right-angle chevron form similarly directed and with the arms directed at 45 to the length of the bar, the pitch measured between the apices of successive slots being not greater than the hypotenuse measured across the arms of each slot, the apices of the slots of each bar lying on a line parallel to the long axis of the bar, and a bolt passing through a slot intersection point in each of three pairs of overlapped flanges of the said bars .to secure said bars in rigid relationship.

5. A constructional element comprising a bar of rightangle L section having flanges of diflerent width, a plurality of similar right-angle chevron shaped slots with axes similarly directed and, said slots being spaced at equal intervals along the entire length of each flange with the arms of said slots directed at 45 to the length of the bar, the apices of the slots all lying on a line parallel to the axis of the bar and the slots being so arranged that when two bars are placed at right-angles with a flange of each bar in plane contact partial overlap is obtained between at least one slot in each of said contacting flanges, said overlap being suflicient to allow at least one position for a fixing bolt of diameter equal to the slot width to pass through both of said flanges.